A few days ago my spedo on my '64 V90 started acting up. At first it was really loud and bounching all around the dial. Now it just bounces between 10-20 mph with less noise, but won't go beyond 20. I have a feeling its a problem with the cable, but I don't know where to start. Could you guys help me out?

pull it out and check the cable. make sure the end is still square and the speedo insert is still square. if it looks good on that end then pull the cable off down by the wheel. there's some things in there that can go bad.
it sounds like it's maybe rounding out the cable end and isn't catching on every rotation.
-a